function setCookie(name,value){
    document.cookie = name + "="+ escape (value);
}
function getCookie(name){
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)"); //正则匹配
    if(arr=document.cookie.match(reg)){
        return unescape(arr[2]);
    }
    else{
        return null;
    }
}
//删除cookies
function delCookie(name){
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
    if(cval!=null){
        document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString() + ";path=/"
    }
}
